My application has two classes: exampleAppDelegate and exampleController. 
I import exampleController.h into exampleAppDelegate.m and exampleAppDelegate.h into exampleController.m.
When I try to use outlet or action from exampleController class in exampleAppDelegate class, the compiler returns the following error: 
use undeclared identifier and action not found.
The same problem happens when I try to use the variable from exampleAppDelegate in exampleController. 
What am I doing wrong?